More people are getting bigger, requiring more food

Globally, human consumption increased by 129 per cent during this time span. Population growth was responsible for 116 per cent, while increased weight and height accounted for 15 per cent. Older people need a little less food, but an ageing population results in only two per cent less consumption.

“The additional 13 per cent corresponds to the needs of 286 million people,” Vásquez says.

This in turn corresponds approximately to the food needs of Indonesia and Scandinavia combined.

Major differences
Considerable variations exist between countries. Weight gain per person from 1975 to 2014 ranged from 6 to 33 per cent, and the increased energy requirement ranged from 0.9 to 16 per cent.

An average person from Tonga weighs 93 kilos. An average Vietnamese weighs 52 kilos. This means that Tonga people need 800 more kilocalories each day – or about four bowls of oatmeal.

Some countries are changing quickly. On Saint Lucia in the Caribbean, the average weight rose from 62 kilos in 1975 to 82 kilos 40 years later.

The lowest and highest changes are found in Asia and Africa, reflecting the disparities between the countries of these continents.

Not previously calculated
“Previous studies haven’t taken the increased demands of larger individuals and aged societies into account when calculating the future food needs of a growing population,” said Vásquez.

Most studies estimate that an average adult’s food needs remain constant over time and fairly similar across nations. But that’s not how it is.

“These assumptions can lead to errors in assessing how much food we’ll actually need to meet future demand,” Vásquez says.

This study provides relevant information for the UN’s Food and Agriculture Organization (FAO), which is a leader in the struggle to ensure food security for all.

Vásquez and Vita say that we have to look at more than just the number of people in an area to understand the mechanisms behind their consumption. This requires a multidisciplinary approach that considers both social and physiological factors.

This study’s analysis involved bio-demography, a hybrid of biology and demography. The researchers adapted a model for dynamic systems that is often used in industrial ecology to study resource stocks and flows.

— Read more in Felipe Vásquez et al., “Food Security for an Aging and Heavier Population,” Sustainability 10, no. 10 (2018) (doi: org/10.3390/su10103683)

The article is published courtesy of Gemini, which publishes research news from NTNU: Norwegian University of Science and Technology and SINTEF